Ready-made cusp



May 26, 1931 I RAYMOND 1,807,072

READY MADE CUSP Filed May 22. 1929 l atentecl May 26, 193i I UN l T a stares PATENT F CE LOUIS RAYMOND, on NEW YORK, N. Y., ASSIGNOR T0 BAKER & co. INQ, A conrone 'IION on NEW JERSEY READY-MADE cnsr Application filed May 22,

' This invention relates in generalto so-called ready-made gold cusps for crown and bridge work. These cusps usually comprise pieces of gold which have been shaped toconform to the occlusal surface of a natural tooth, and

are combined with an artificial tooth facing and a backing of gold solder or the like.

In applying such cusps to artificial tooth material, which when hardened serves to hold the cusp and the tooth facing in the proper relation while gold solder or the like is melted and flowed into the cusp and in back of the tooth facing. The gold solder serves to securely attach the facing to the cusp, and also as a backing or reinforcement for the cusp. During this operation it has been found that as the solder hardens and contracts,'it pulls the cusps out of the mold or cast into an abnormal and improper relation to the tooth facing.

Among the objects of my invention are to provide a novel and improved method of making artificial teeth including sheet metal cusps, facings and backings of solder, and

to provide a ready-made cusp of the general character described embodying novel and improved features of construction whereby the cusp may be securely held in the investment material or mold and reenforced against distortion during the application of the backing solder.

Other objects are to provide such a cusp having a projection or protuberance thereon which may be imbedded in the investment material in such a manner as to prevent the cusp from being accidentally pulled out of the material; to provide a ready-made cusp of this character wherein the projection or protuberance can be easily removed and in no way impairs thevfinished artificial tooth; to provide a'cusp of this character which can be f easily and economically manufactured, and

to obtain other advantages and results as will be more fully brought out by the following description.

Referring to the accompanying drawings,

1929. Serial-No. 365,933.

in which corresponding and like parts are "'7 designated throughout the several views by the same reference characters,

Figure 1 is atransverse vertical sectional view throughtan .artificial tooth including a cusp embodyingmy invention, showing the tooth arranged in a block or mold of plaster or investment material, and

Figure 2 is a composite perspective view of two cusps of different sizes embodying my invention.

Specifically describing the illustrated em bodiment of the invention thereference characters 1 and 2 designate two ready-made cusps of different sizes, each of which comprises a. sheet of gold or other suitable metal which is shaped to substantially conform to the occlusal surface of a natural tooth. The front side 3 of each of the cusps is adapted to accurately contact with the occlusal edge 4 of an'artificial tooth facing 5; of known construction which includes the usual metal backing plate 6 and facing pins 7 projecting from the rear of the facing. The opposite side of the cusp is shown as provided with one or more integral projections, protuberances, tongues or lugs 8' which maybe formed dur-I ing the shaping of the cusps. In making an artificial tooth including a cusp embodying my invention, the facing 5 and cusp- 1 or 2 are arranged in the proper relation vwithin a mold or block of plaster or investment material 9 which is initially plastic and'is capable of hardening. The in- ;vestme'nt material is caused to overlie the wardly into the material as indicated at 10 so that said lugs are in effect imbedded in the material. Molten solder 11 is then flowed into the mold into contact with the backing plate 6 and the cusp 1 to firmly secure the cusp to the facing and to provide a reinforcement for the cusp. During this operation the lugs 8 securely hold the cusp against movement in the investment or mold, and resist the tend ency of the hardening and contracting solder to draw the cusp out of the investment into improper relation to the facing 5. Also, the lugs reenforce the edges of the cusps to preventdistortion or. deformation thereof during'the soldering operation. After the tooth has been completed the mold is broken away from the tooth which is thereby removed from the mold; and thereafter the protuberances 8 may be burnished ofl' so as to' leave a smooth outer surface on the cusp. 7

It will be understood that while the embodiment of my invention above described is the now preferred one, the detail construction of the cusps maybe modified or changed by those skilled in the art without departing from the spirit or scope of my invention which is defined by the appended claims when construed in the light of theprior art.

Having thus described my invention, what I claim-is: .1

1. As an article of manufacture an artificial tooth cusp comprising a sheet of metal shaped to simulate the occlusal surface of a tooth and having a projection on the lingual side thereof to be imbedded in a plaster mold during thesoldering operation in making an,

artificial tooth to hold said cusp against movement in therplaster and reenforce the edge of the cusp against distortion.

2. As an article of manufacture an artificial tooth cusp comprising a sheet of metal shaped t'ofsim'ulate the occlusalsurface of a tooth'andhaving an integral lug projecting from the lingual edge thereof to be imbedded in a plaster investment to hold the cuspagainstlmovement therein and reenforce the edge of the cusp against distortion during the soldering of said cusp to a tooth-s facing in the making of an artificial tooth.

' LOUIS RAYMOND. 

